“We’re aware that many players are receiving Error 37 when logging into the game. Please note that this error indicates that all servers are full, and that we’re currently receiving a high volume of login traffic. We’re working to reduce the frequency at which players are prompted with this error message and ensure that everyone can successfully log in to the game and play.”

Despite the reassurance, the European servers are currently offline.

It’s unclear whether the issue was related to today’s release of the very first full patch for the game.

The patch contains another nerf for the (apparently overpowered) Monk class, as well as several bug fixes and a slew of updates for the auction house. See the full notes here.